Considerable interest has existed in the copolymerization of acrylates with norbornenes because of the potential benefits of combining the useful properties of the homopolymers of the two monomers. For example, polyacrylates are valued for their extreme hardness and adhesive properties, and are used to form clear, glass-like materials such as Lucite.RTM. and Plexiglas.RTM.. Polynorbornenes, on the other hand, are capable of resisting high temperatures and, thus, typically are employed in applications that necessitate high-temperature stability.
Until the present invention, attempts to copolymerize acrylates with norbornenes have been unsuccessful because of a disparity in the mechanisms by which the respective monomers polymerize. Typically, acrylates polymerize in the presence of radical or anionic initiators, whereas norbornenes do not follow radical pathways and normally are polymerized by cationic or insertion mechanisms. Therefore, in order to effect the copolymerization of acrylates with norbornenes, it was necessary to develop a catalyst system that would be effective for polymerizing both types of monomers.